Let the original volume be pi *r^2* h where r = radius and h = height.
The new volume will be pi *(2/5 r)^2 * 4h = pi*4/25 r^2 4h
pi*4/25r^2 * 4h / pi r^2 h = 4/25 * 4 = 16/25
The volume has been reduced by factor of 16/25.
132 because 11 times 4 times 3 is 132. Forget the 5 because the 11 and 5 is measuring basically the same thing.
40 boys and 68 girls
let's start with variables and an equation.
boys: x
girls: 2x - 12
and we know that boys and girls make up the class. so let's add the two expressions.
x + 2x - 12 = 108
3x - 12 = 108
+ 12 + 12
3x = 120
x = 40 boys
BUT x is only the number of BOYS in the class. so we have to find girls now. let's plug in our value of x into the girls' equation.
2x - 12 = # of girls
2(40) -12 = # of girls
80 - 12 = # of girls
68 girls
let's check our answer!
68 + 40 does in fact add to 108, therefore our answer is correct.
Since JL = 12 inches, that's the amount for AC
